1. Field of the Invention
The present invention relates generally to mattress assemblies and, more particularly, to one-sided mattress assemblies that offer significant reduction in the amount of permanent deflection resulting from the compaction of padding materials under normally encountered loads.
2. Description of the Related Art
A conventional inner spring mattress as known in the bedding industry generally comprises a resilient construction consisting of two sleep surfaces (top and bottom) enclosing an assembly of wire springs. The springs are typically covered over with padding on the top and bottom surfaces and the whole assembly is encased within a ticking, often quilted, that is sewn closed around its periphery to a border or boxing. For many years one preferred form of spring assembly construction has been known as Marshall construction. In Marshall construction individual wire coils are each encapsulated in fabric pockets and attached together in strings which are arranged to form a closely packed array of coils in the general size of the mattress. Examples of such construction are disclosed in U.S. Pat. No. 685,160, U.S. Pat. No. 4,234,983, U.S. Pat. No. 4,234,984, U.S. Pat. No. 4,439,977, U.S. Pat. No. 4,451,946, U.S. Pat. No. 4,523,344, U.S. Pat. No. 4,578,834, U.S. Pat. No. 5,016,305 and U.S. Pat. No. 5,621,935, the disclosures of which are incorporated herein by reference in their entireties.
Conventionally, inner spring mattresses have identical top and bottom surfaces. During normal life of such conventional mattresses some degree of permanent deflection, or sag, can develop in the mattress surfaces due to compaction of the component padding materials. This permanent deflection can interfere with the mattresses' intended function of providing a supportive and resilient sleep surface. Inner spring mattress manufacturers recommend periodically rotating and turning over the mattress utilizing the top and bottom sleep surfaces in order to counteract, minimize and/or delay the aforementioned permanent deflection. Under continued use, this compaction becomes more permanent. The degree of permanent deflection is directly related to the type and amount of padding installed both over and under the wire spring assembly. To remedy this shortcoming, manufacturers utilize materials that produce less permanent compaction. These materials are generally more dense, but can be less comfortable and more expensive.
Accordingly, it is desirable to provide an inner spring mattress assembly which exhibits a reduced amount of permanent deflection due to compaction of padding materials while at the same time exhibiting substantial comfort in use. It is further desirable to provide such a mattress assembly that can be constructed by conventional known manufacturing techniques. Still further, it is desirable to provide such a mattress assembly that is cost-effective to produce.